외국인력 및 이민 유입의 경제적 영향

최경수,Choi, Kyungsoo 한국개발연구원 2012 韓國 開發 硏究 Vol.34 No.2

외국인력 및 이민 유입은 경제 전반에 걸쳐 저숙련 노동공급을 증가시키는 효과를 가진다. 그 영향으로부터 완전히 독립적인 통제집단은 경제 내에 존재하지 않기 때문에 효과평가방법(impact evaluation method)에 의한 영향평가는 한계를 지닌다. 본 연구에서는 총요소비율 접근방법(aggregate factor proportions approach)을 채택하여 경제 내 저숙련 노동공급 증가의 효과를 추정함으로써 외국인 유입의 영향을 평가한다. 평가 결과는 외국인력 및 이민 유입은 숙련 노동력과 저숙련 노동력 간의 임금격차를 상당히 확대시키는 반면, 성장에 대한 기여는 크지는 않음을 제시한다. 그 이유는 국내에 유입되는 외국인력의 절대다수가 생산성이 낮은 단순인력이라는 데에 있다. Inflow of foreign workers and immigrants increase the supply of unskilled labor in the economy. In measuring their impacts, an impact evaluation method produces unreliable estimates because a control group independent from their impacts is hardly found within the economy. This study adopts an aggregate factor proportions approach and measures the impacts by estimating the effects of skills proportion changes in labor supply on relative wages. The estimation uses two and three skills groups categorized by education levels. The study reveals that foreign workers and immigrants contribute to economic growth by a small margin while they significantly widen the wage gap between native skilled and unskilled workers. The result is based upon the fact that the existing foreign workers and immigrants are predominantly the least skilled groups. The estimates can be applied in predicting the impacts of labor inflow from North Korea which always remains as a possibility in Korea.

파일롯 규모의 운영에 따른 하천수질(T-P) 개선에 관한 연구

최경수,이채영,Choi, Kyoungsoo,Lee, Chaeyoung 대한상하수도학회 2021 상하수도학회지 Vol.35 No.5

Pilot-scale coagulation and sedimentation processes were operated to investigate the T-P (Total phosphorus) removal efficiency. A multiple regression model was also derived to predict the water quality improvement effect with river water characteristics. The inflow rates for the pilot-scale facility were 157-576 m³/day, and the coagulant doses were in the range of 13.7-58.5 mg/L (average 38.9 mg/L) for PAC (Poly alum chloride) and 16.5-62.1 mg/L (average 36.0 mg/L) for alum. The results found that the influent BOD (Biochemical oxygen demand) and T-P concentrations were 4.9 mg/L and 0.115 mg/L, and the removal efficiencies were 52.7% and 59.4%, respectively. T-P removal efficiencies on wet weather days were higher by 10% than dry weather days because influent solids influenced T-P's coagulation process. The pH of river water was 6.9-7.8, and the average pH was 7.3. Although the pH variation was not significant, the trend showed that the treatment efficiency of T-P and PO₄-P removal increased. Thus, the pH range considered in this study seems to be appropriate for the coagulation process, which is essential for phosphorous removal. The T-P removal efficiencies were 19.6-93.3% (average 59.2%) for PAC and 16.4-98.5%(average 55.9%) for alum; thus, both coagulants showed similar results. Furthermore, the average coagulant doses were similar at 42.4 mg/L for PAC and 41.3 mg/L for alum. When the T-P concentration of the effluent was compared by the [Al]/[P] ratio, the phosphorus concentration of the treated water decreased with an increasing [Al]/[P] ratio, and the lowest T-P concentration range appeared at the [Al]/[P] ratio of 10-30. A seasonal multiple regression analysis equations were derived from the relationships between 10 independent and dependent variables (T-P concentration of effluent). This study could help lake water quality maintenance, reduce eutrophication, and improve direction settings for urban planning, especially plans related to developing waterfront cities.

톤버스트 응답 신호의 스펙트럼 추정에 의한 배터리의 SoC 측정에 관한 연구

최경수,강대수,Choi, Kyoung-Soo,Kang, Dae-Soo 한국인터넷방송통신학회 2018 한국인터넷방송통신학회 논문지 Vol.18 No.1

The deterioration of the Battery is decided by SoC and SoH. To determine Battery deterioration, SoC measurement method of Battery by Transfer Function was studied. The SoC of the Battery changes most greatly in the 1Hz band where the DC resistance is detected. but it is a narrow band to observe, therefore, the observation band was moved to 1kHz using the tone busrst signal. Welch's method was used to observe the frequency domain characteristics of the signal. As a result of the spectral estimation, it was confirmed that the response signal of the battery is 1dB difference when the SoC is 40%, 60%, and 80%, respectively. Through this, Proposed the new method of Battery SoC measurement. 배터리의 열화는 SoC 및 SoH의 변화에 따라 결정된다. 배터리의 열화를 판정하기 위해 전달 함수에 의한 배터리 SoC를 측정 하는 방법을 연구 하였다. 배터리의 SoC는 DC 저항이 검출되는 1Hz 대역에서 가장 크게 변화 한다. 하지만 관측하기 협소한 대역이기 때문에 톤버스트 신호를 입력신호로 사용하여 배터리의 주파수 응답대역을 대역을 1kHz로 이동 시켰다. 신호의 주파수 영역 특성을 관측을 위해 Welch스펙트럼 추정 방법을 사용하였다. 스펙트럼 추정 결과 배터리의 응답 신호는 SoC가 40%, 60%, 80% 일 때 각각 1dB의 차이를 갖는 것을 확인 하였으며, 이를 통해 새로운 배터리 SoC의 측정 방식을 제안 하였다.

실험계획법을 이용한 플라즈마 단열코팅에 관한 연구

최경수,박동화 ( Kyung Soo Choi,Dong Wha Park ) 한국공업화학회 1995 공업화학 Vol.6 No.5

플라즈마 용사(spraying) 공정을 이용하여 형성한 단열코팅층에 대한 연구를 수행하였다. 이 단열코팅은 공구강(KS 규격 : STD61) 기판위에 8wt%의 이트리아로 부분안정화된 지르코니아 분말을 사용하여 코팅하였으며, 본드코팅층은 니켈합금 분말을 사용하였다. 실험계획법으로서 플라즈마 용사 공정의 주된 영향을 미치는 인자를 선정하였고, 이에 대한 분석은 통계분석법 중 하나인 분산분석을 행하였다. 코팅층의 미세조직 및 기공도는 전자주사현미경과 영상분석기등을 사용하여 관찰하였고, 코팅의 품질은 단열효과, 열충격시험에 대한 저항성 등으로 평가하였다. 또한 기판과의 접착력 시험을 행하였다. 고도의 단열코팅층을 형성하기 위한 최적의 플라즈마 용사 공정변수는 실험계획법과 통계적 분석방법을 통하여 찾아낼 수 있었다. The formation of thermal barrier coating(TBC) layer using plasma spraying process was studied. Zirconia(partially stablized with 8wt% Yttria) coating was prepared for the TBC by plasma spraying on tool steel (KS : STD61) substrates. NiCrAlY powder was sprayed as a bond coating layer. Design of experiments was used to derive the main parameters of processing and determined the process parameters according to the analysis of variance. The microstructure and porosity of the coating were characterized using SEM, Image analysis etc. Coating qualities are discussed with respect to thermal barrier effects and thermal cycling test. And adhesive strength test was carried out. Optimum coating parameters which were derived from the statistical analysis could be found for high quality TBC.

온라인 시험 및 평가 시스템 설계 방안

최경수,이길흥,Choi, Kyungsoo,Lee, Kilhung 디지털산업정보학회 2017 디지털산업정보학회논문지 Vol.13 No.1

This paper describes a design scheme of a system that tests or polls from the students at online class. By online test, the teacher can test the pre-knowledge level of the students and know how much students understand the lecture of the class. As the number of test increases, the burden of the preparation of setting question, evaluation of the test, and management of the test results is increased. In this environments, an online test management system make it easy to test and evaluate, and thus it would be a good tool for maintaining and managing the total procedure of the test or poll of the students. For evaluating the design of the system, we made a test system prototype and performed evaluations of the online test system. The online test and evaluation system provides a good tool for testing and evaluation of student's knowledge at the class with easy and fast way.

학술발표회 초록 ( 재료 Poster 발표 ) : 실험계획법을 이용한 플라즈마 단열코팅

최경수,박동화 ( Kyung Soo Choi,Dong Wha Park ) 한국화학공학회 1994 추계학술발표회 Vol.- No.-

ABS 수지상의 도금층 형성을 위한 에칭 방법 연구

최경수(Kyoung Su Choi),최기덕(Ki Duk Choi),신현준(Hyun Jun Shin),이상기(Lee Sang-ki),최순돈(Soon Don Choi) 한국표면공학회 2014 한국표면공학회지 Vol.47 No.3

In the present study, we successfully developed an eco-friendly chemical etching solution and proper condition for plating on ABS material. The mechanism of forming Ni plating layer on ABS substrate is known as following. In general, the etching solution used for the etching process is a solution of chromic acid and sulfuric acid. The etching solution is given to the surface resulting in elution of butadiene group, socalled anchor effect. Such a rough surface can easily adsorb catalyst resulting in the increase of adhesion between ABS substrate and Ni plating layer. However a use of chromic acid is harmful to environment. It is, therefore, essential to develop a new alternative solution. In the present study, we proposed an eco-friendly etching solution composed of potassium permanganate, sulfuric acid and phosphoric acid. This solution was testified to observe the surface microstructure and the pore size of electrical Ni plating layer, and the adhesive correlation between deposited layers fabricated by electro Ni plating was confirmed. The result of the present study, the newly developed, eco-friendly etching solution, which is a mixture of potassium permanganate 25 g/L, sulfuric acid 650ml/L and phosphoric acid 250ml/L, has a similar etching effect and adhesion property, compared with the commercially used chromium acid solution in the condition at 70oC for 5 min.

멀티빔위성망 감시제어 기능설계

최경수(Kyung Soo Choi),조진호(Jin Ho Jo),신천식(Cheon Sig Shin),이성팔(Seong Pal Lee) 대한전자공학회 2004 대한전자공학회 학술대회 Vol.2004 No.12

산업연관표를 이용한 업종별 과표 양성화율 추정

최경수(Choi Kyung Soo),전병목(Jeon Byung Mok) 한국국제조세협회 2006 조세학술논집 Vol.22 No.2

This paper estimates the income report ratio of self-employed by comparing Input-Output Table and tax return data. We decompose the income report ratio into sales report ratio and net-of-cost share report ratio. Our results show that low income report ratio is derived from poor sales report ratio, approximately 51.2% at 2000. Net-of-cost share report ratio is relatively close to the real cost structure due to government's guidelines and lack of taxpayer's interest. This implies that we need to build more clear transaction system for higher sales report ratio.

조세피난처 세제적용의 국제적 과세동향과 그 시사점

최경수(Kyung Soo Choi),최용환(Yong Whan Choi) 한국국제조세협회 2008 조세학술논집 Vol.24 No.1

The benefits reaped from engaging in a tax-avoidance activity have been subject to abuse by resident enterprices through retainig gains in the foreign subsidiariese usually located in the tax havens. In case of korea, it is of recent issue to cope with the International Tax Evasion through Tax Havens. Since It has passed only 10 years since korea introduced CFC legislations, systematic taxation skills and precedent cases have not yet accumulated. also United states which adopted CFC rule first is the second larestcountry of foreign direct investment on korea's side and many korea-based multinational enterprises are expected to be subject to the US CFC legislation. and for japan, CFC rules are much similar to that of korea's and several cases which can also arrise in korea were judged by the jurisprudence. But previous studies have been only focuced on the study of CFC Rules conducted by comparative analysis of major foreign country's CFC legislations. So in this study we scrutinized US and japan's jurisprudences and taxation systems as well as CFC legislations including the Inversion trasactions which try to evade CFC applications